Stuffing box



Oct. 20, 1931. l. LUNDGAARD STUFFING' BOX Filed Aug. 5, 1925 fim/ervio 2* Q fia/rzundgaaard CD \b 59%, My 14W, 05 2295 Patented Oct. 20, 1931 UNITED STATES PATENT OFFICE,

IVAR LUNDGAARD, or WORCESTER, MASSACHUSETTS, ASSIGNOR To DEVON MANU- FACTURING COMPANY, or BosToN, MASSACHUSETTS, A CORPORATION or MASSA- CHUSETTS STU TING BOX Application filed August 5, 1926. Serial No. 127,293.

I This invention relates to a stuifing box construction which is adapted to use in a wide variety of installations wherein'it is desirable to have a revolving shaft. project through the wall of a casing upon Opposite Sides of which different fluid pressures prevail.

A stufling box of the type disclosed herein is more particularly intended for use in refrigerating apparatus using air as a mediatjb ing fiuid,lsuch as'disclosed-"in my Patent No.

l,2 i( ,862, or in a machine of the same general type in'which the averageinternal pressure is considerably higher than the, atmospheric M pressure; .It will, however, be evident that 3 a stuiiing box construction of this type, which isadapted to provide an eflicient, oil seal at a-mimmum expense, will be equally useful in numerous locations, as, for example, in

, pumps, motors, internalcombustion engines,

" 26 particularly of the two-cycle crank case compression type, and many other machines.

The present invention provides a very inexpensive,'stufiing box construction which is P adapted to maintain a substantially air-tight 2'5 oil seal about. a revolving shaft and indeed to retain air at considerable pressure within a casing and in some respects it may be considered tobe an improvement upon a sim- M plification of the construction disclosed in a my pending application Serial ,No. 127,294,

filed on ,ei en date herewith.

" In a machine of this class provided with reciprocating parts, such as pistons, connecting rods andthe) like, and having a main 3% shaft-in which there are crank throws, etc., there is always a degree ofvibration or whip in the crank shaft which may be merely perceptible, but which, however, is suiiicient seriously to interfere with the. maintenance "40 of a bearing fit accurate enough to prevent the escape of air. While the amount of such vibration may notube so great as the normal oil clearance in the main journal bearing a... provided with splashv lubrication, such a condition is prone topermit considerable oil leakage and leakage of air suspended therein. It is therefore necessary to provide special means for retaining a "bearing member in I closeengagem'ent witha portion of the re- 5i volving shaft and yet to compensate for the slight vibrations occurring during the 'rota-.

tion of the shaft as well as slight irregularities in alignment, workmanship, etc. It is furthermore desirable to provide such a bearing member with its close bearing fit upon an annular shoulder of the shaft rather'than upon the cylindrical bearing portion thereof, since the degree of vibration may be some what lower and since the bearing Stresses resulting from the weight of the shaft and centrifugal and inertia forces are not directly borne. In a device of this type it is often possible to have an annular bearing member merely act as athrust bearing to balance the internal pressure acting upon a portion of the shaft, and such a construction is disclosed inthe present embodiment of the invention; it having been found in practice that a layer of fibrous material, preferably paper which is somewhat compressible and of the character used for gaskets or the like is adapted to comprise suitable backing for an annular bearing member with a flange in engagement with a shoulder on the revolving shaft, to retain the bearing member in comparatively tight fit there'against, yet to compensate for minor vibrations and variations in alignment, fitting, etc. and when associated with a suitable oil seal to provide'a practically air-tight construction.

One specific embodiment of the invention is disclosed in the accompanying drawings, in which:

Fig. 1 is a vertical Cross-section of the crank case of a machine embodying my improved stufling box construction; and

Fig. 2 is a detail sectional view of the same.

For the purpose of illustration, I have shown my improved stufiing box as it is installed in the crank case of a refrigerating machine adapted to useair as a mediating fluid; F orexample, in a machine of this type the air in the crank easel may normally be under an average pressure which will be equal totwo or three atmospheres. The machine is actuated by a suitable crank shaft 2 which is driven by a pulley 3 keyed upon an overhanging projection of the shaft, The opposite end of crank shaft 2 is mounted in a suitable bearing 4 within the case 1.

The improved stufling box construction which more particularly forms the subject matter of the present invention is located in the wall of the crank case, or the motor end adjoining the overhanging projection of the shaft. This motor end may preferably be provided. with adouhle wall indicated by the numerals 6 and 7,and forming an annular oil chamber 19 therebetween which communicuteswith the interior of the crank case 1. Attire-centre of chamber 19 is located a boss 8 which holds a bearing 9 adapted to en age the c lindrical portion 10 of the crank 2. e end of the cylindrical portion 10 of the shaft is defined by a shoulder 11 and ti}: rem 'ning overha irng portion of the sha is of .a reduced d ilimeter. Preferably the bearing 9 has an inturned flange or shoulder 13 adapbed to project inwardly toward the ofthe-shaft 2, but spaced somewhat from shoulder of the shaft.

under to provide a substantially airtighthearingfor the shaft 2, a bushing 16 is located in the interned flange portion 13 of thoboaring member 9 and has an out-turned annular flange 17 in engagement with the upon the revolving shaft. Between theinturned flange upon the bearing and the 'ul ltturned flange upon the bushing 16 is 10- Gated a washer or gasket 21 of compressible material, preferably fibrous material such as paperof about a thirty-secondth of an inch 111 flliolmess, which is adapted to hold the W 1.7 in firm, but slightly yieldable, engagegnent with the shoulder upon the revolvufishaft, or in :other words the compressih yflof the paper permits a minute movement of the bushing 16 with its flange 17 to compensate for flexures in the shaft 2 and minor inaccuracies in workmanship, fitting, orgtht like in the bearing and shaft. The annularoil groove adjoining the flange 17 .to provide an oil seal at this point andmlybe connected withthe chamber 19 by duct 32 to receive sufficient oil. Normally the minrnal air pressure will tend to press the crankshaft endwise into comparatively firm engagement with the flange 17, and the oil seal provided adjoining the flange in combination with theolose engagement of the flange and shoulder will ,prevent practically all leakof air from the casing 1. It is .to be understood that between the shaft 2 and the member .9 as well as the cylindrical ion'ofthe bushing 16, the usual clearance .the oil film may be provided, While the annularthmge 17 is adapted to bear upon the shouldor of the shaft with but.a minute clearwhich isnot suificient to allow the leak- .9 anappreciable amount ofoil, and contmflequontly the leakage of air suspended Spaced-outwardly from the end of the bearmg 9 and the flange 17 may be a suitable chamber 18 formed in the crank case 2 and provided with a downwardly extending duct 20 which is adapted to guide oil which leaks outwardly along the bushing 16 into a suitable sump below the crank case in order to conserve the oil supply.

Ordinaril it will not be found necessary to lock the udiing 16 in the bearing except by an ordinary press fit. However, if desired, positive locking means may be provided as illustrated; for exam Ie, the bushing and bearing flange 13 may drilled to receive a locking pin 22 (Fig. 2).

It is-evident that in the manufacture of a stufling box of this type the only point requiring especially accurate fitting or la ping is the restricted bearinganea between eflange 1.7 and the shoulder upon the crank therefore, that the present invention requires the minimum of skilled labor and ofaccurab fitting or assemblying and that it .di aw with the need of expensive and comp mated packings or gaskets in order to provide a practically air-tight stuiing .box.

I claim:

1. A stufling borx construction comprisinga shaft adapted to revolve, a relatively filed casing including a bearing portion throu which the shaft extends. a shoulder upon shaft adjoining one end of the bearing portion, a bushing with its body portion engaging the casing provided with an ammlar flange in close bearing engagment with the shoulder on the shaft, and an annular paper gasket between the flange and the fixedoasing adapted to hold the flange in firm but slightly 'yieldahle engagement with the .mvolving shoulder.

2. A stuffing box construction comprising ceasing in which internal pressureis ad to behigher than external preesum. a 8ft adapted to revolve in the-casing and having one and projecting therefrom, a hear at the side of the casing through which the projects. an oil chamber in the casing mmmunicati ng'with. said hearing, a portion-of the shaft engaging said bearing, :a shoulder on the outer end of said portion, a bushing having an annular end portion in bearing-engayment with said shoulder and .a paper retaining said end portion in firmibut slightly yieldable engagement with the shoulder on the shaft which is normally pressed against the flange by internal pressure in Hue casing.

3. A stufiing box construction comprising a casing in which internal premure isnduntd to be higher than exitemal pmssune. a shaft adapted to revolve in the casing and having one end projecting therefrom, a at the side of the casing through which the shaft projects, an tlilil .chdaiieller in the casing communicating wit sai r.i mlttlng' the drainage of oil fromsaid tosail bearing, a portion of the shaft engagingeaid bearing, a shoulder on the outer end of said portion, a bushing having an annular and m 

